A search for methane in the atmosphere of Mars using ground-based mid infrared heterodyne spectroscopy

作者：Sonnabend G^*; Stupar D; Sornig M; Stangier T; Kostiuk T; Livengood T A

来源：Journal of Molecular Spectroscopy, 2013, 291: 98-101.

DOI：10.1016/j.jms.2013.05.009

• Planetary atmosphere
• Remote sensing
• Spectroscopy
• Methane

We report our search for methane in the atmosphere of Mars using high-spectral resolution heterodyne spectroscopy in the 7.8 mu m wavelength region. Resolving power and frequency precision of %26gt;10(6) of the technique enable identification and full resolution of a targeted spectral line in the terrestrial-Mars spectrum observed from the ground. Observations were carried out on two occasions, in April 2010 and May 2012 at the McMath-Pierce Solar Telescope and the NASA Infrared Telescope Facility, respectively. A single line in the nu 4 band of methane at 1282.62448 cm(-1) was targeted in both cases. No absorption due to methane was detected and only upper limits of 100 ppb for the martian atmospheric methane concentration were retrieved. Lack of observing time (due to weather) and telluric opacity greater than anticipated led to reduced signal-to-noise ratios (SNR). Based on current measurements and calculations, under proper viewing conditions, we estimate an achievable detection limit of similar to 10 ppb using the infrared heterodyne technique - adequate for confirming reported detections of methane based on other techniques.

• 出版日期2013-9